Traditionally, many surgical procedures for both open surgery and minimally invasive surgery (i.e., endoscopic, laparoscopic, or arthroscopic surgical procedures) have utilized surgical tools such as scalpels, scrapers, blunt dissectors, lasers, electrosurgical devices, etc., which can have poor tissue differentiating capability, which may easily cause inadvertent damage to tissue surrounding a surgical treatment site, and which do not typically provide for an ability to precisely control a depth of cutting and/or tissue ablation with the instrument and/or effectively provide for evacuation from the treatment site of cut/ablated tissue. Many such surgical procedures can entail more extensive trauma to the patient and/or require longer operating procedures, with associated problems of long recovery periods and potential complication, than is desirable.
Instruments that employ liquid jets have also been utilized in surgical procedures for cutting and ablating tissue. Such instruments can have certain advantages over the above-mentioned traditional surgical instruments for performing surgical and medical procedures. For example, the cutting or ablating power of the liquid jet may be adjusted or controlled by an operator of the instrument, for example by varying the pressure of the liquid supplied to form the jet, to allow for improved tissue differentiation and to reduce inadvertent damage to surrounding tissues when cutting or ablating the target tissue. When operated at lower liquid pressures, the instruments can be utilized for lavage and/or debridement of tissue, without substantial cutting. A variety of such liquid jet surgical instruments for performing open surgical procedures, minimally invasive surgical procedures, and surgical procedures performed on an external portion of the body of a patient (e.g., wound cleansing or skin debridement) are known in the art. Several such instruments are described in the Applicants' U.S. Pat. No. 5,944,686, issued Aug. 31, 1999, U.S. Pat. No. 6,375,635, issued Apr. 23, 2002, and U.S. Pat. No. 6,451,017, issued Sep. 17, 2002, each hereby incorporated by reference.
Several factors can be important to the functional performance of a liquid jet instrument used for surgical procedures or other medical applications. In many surgical or medical procedures, it is desirable to be able to control or select the depth to which a surface of a tissue is cut or ablated with a surgical instrument. In addition, in some surgical and medical procedures (e.g., wound cleansing) it can be desirable to perform effective cleaning and lavage of a tissue surface and/or selective removal of contamination and/or necrotic tissue from such surface without substantial cutting or ablation of healthy tissue. While many of the above-mentioned prior art surgical instruments, and especially liquid jet-based surgical instruments have utility for performing such surgical and medical procedures, there remains a need in the art for surgical instruments, especially liquid jet-based surgical instruments, providing enhanced control over the degree and extent of cutting and/or ablation with the instrument. The present invention provides, in certain embodiments, such improved surgical liquid jet instruments, and further provides methods for their construction and use in a variety of surgical procedures.